Snapped head stud

If the stud is in SO tight, that it broke, I doubt that the extractor idea will work.

Use a small die grinder, and put a dimple in the stud........it MUST be in the center of it. This will guide any drill bit down the center. You must make sure the drill bit is perpendicular to the stud lenght. Use a small drill bit and drill down the center of the stud, all the way through Then, use a bigger bit, and go through the stud. Continue using larger size bits, till you get to one that is slightly smaller than the stud hole. Often the remains will now come out.

If the thread, in the block is damaged, then you will have to HeliCoil it. You will have to use the drill bit that they recommend, that will coincide with the original stud thickness, and thread, when finished. I have done this, and the hole drilled, for the HeliCoil, is only minimally larger than the original hole. Of course, the stud will still have to come out before drilling for the HeliCoil.

 

You may very well have to yank the engine and have a machine shop extract it for you. Consider that route before you butcher the block. Sometimes its just better to bite the bullet and have someone with access to the right equipment do the job. I cant think of a worse situation and Im dealing with engines daily. Sometimes welding something like a dowl onto the end of the stud gives you something to grab as well as applying heat to the block near the threaded portion of the stud, not to mention praying alot.

 

I agree with Newman. Try welding a large nut onto the top of the stud. You should be able to use a large enough nut to weld from inside and bridge the gap to reach the top of the stud.

This will give you a hexagon to turn the stud and hopefully enough heat around the problem to shift it.

It will be a bastard though.......

 

if it were me: !) warm the block 2) soak the area in marvel mystery oil or similar 3) come back in a day, warm the block some more 4) drill it #40 as deep as possible MUST BE STRAIGHT 5) use a #2 easy out . one time i drilled out one side of an Allen key and installed a easy out ( backwards) i put a box end ratchet wrench on the allen key and removed the stud ( aluminum chevy block.) never fun, good luck to ya!

 

Sitting here thinking about this, with all of this talk of drilling, I can only suggest that the engine be removed and stripped down, because it would be impossible to catch all drill shavings while in place. Then you'd have the problem of little shards of metal that could float around and scratch a cylinder bore, or a bearing... Bigger problems.

With the engine out and stripped down, use an "easy-out" (bolt extractor) in the old stud and a localised application of heat to the block in the area of the stud from an oxy-acetylene torch, spray with a penetrating oil and remove. It will come out then. Warpage from the heat should be minimal and could be cleaned up on a mill. I do this all of the time at work (on less critical pieces than an engine block, but this process takes minutes regardless).

 

When all else fails..... I had the same problem, didn't want to risk damaging the block with excess heat or rethreading, used an EDM shop to take out center of bolt, then extract remainder. Suggested by a F racing shop, worked fine but expensive.
Tom